Django querystring/slug inside of formclass

Is it possibe to get the id slug inside of the get_form_class? Any advice?

class Create(Merchant_Services_Editor_Mixin, CreateView):
    template_name = 'secure/shared/editor.html'

    def get_form_class(self):

        if (self.request.GET.get("id") == 1):
            retu _Merchant_Services_Form.StripeEditor
        else:
            retu _Merchant_Services_Form.BraintreeEditor